Freak of Nature
by Punk Rock Kitsune
Summary: A strange monster enters Mt Ebott from the Surface with three tasks: save a human child, avenge the deaths of six children by killing King Asgore and... kill the one responsible for the resets! Sans has to figure out who this monster really Is, who she's working for, and exactly how much she knows about time traveling. (Warning: Contains heavy spoilers for Pacifist Run and Sans)
1. Chapter 1

**Hey guys! Whoa, it's been almost a year since I've written any fanfiction. I've been battling depression, and didn't feel the spark I needed to write. But thanks to my discovery of Undertale about two months ago, I'm feeling that spark ignite once more.**

 **I do have an OC in this story. She is on the cover I crappily drew. I know opinions of OCs aren't usually that great, since a lot have been self inserts and Mary Sues. I don't blame people for disliking OCs. But I would like to take a second to share with you how important this particular OC is to me.**

 **If you want to read about Polari, go on over to my profile. I really recommend it. With some background, you'll understand why she is the way she is in my story, and how important she was to me growing up.**

 **Thank you for reading my rambling! This is the only long author's note I'll make!**

 **Enjoy the _chapter!_**

* * *

 _ **Story Title:**_ _Freak of Nature_

 _ **Rating:**_ _T_

 _ **Trigger Warnings:**_ _Mentions of rape_

 _Frisk will not be gender specific in this story. I will be using 'they' pronouns._

 _ **Disclaimer:** I do not own Undertale. Credit goes to Toby Fox._

 _ **Summary:** A mysterious monster enters Mt Ebott from the Surface with three tasks: save a human child, avenge the deaths of six children by killing King Asgore and... kill the one responsible for the resets?! Sans has to figure out who this monster really is, who she's working for, and exactly how much she knows about time traveling._

 ** _FINAL SPOILER WARNING:_** _This story heavily spoils the Pacifist run and Sans' knowledge._

* * *

 _ **Chapter 1**_

 _ **~.~.~**_

Flowey scowled as he watched Frisk and Toriel go into the Ruins for the umpteenth time.

"This is ridiculous!" Flowey fumed. "How many times has that brat done this? How many times have they saved everyone? Why do they keep coming back? They just wanna see me suffer…"

A loud thud drew Flowey's attention from the entrance to the Ruins. His petals stiffened.

 _What was that? Hasn't happened before…_

He could sense another presence entering the underground, with a _soul_. In the darkness, Flowey heard soft footsteps. He squinted his eyes.

 _This is something new. Is it another human?_ He sneered to himself. _This'll be fun! Only this time, I'll kill it without interference!_

Flowey grinned evilly, his lust for blood exciting him.

Suddenly, a pair of molten eyes was staring back at the flower, cold and lifeless. Flowey quickly morphed his expression back to a pleasant one, smiling brightly at the visitor.

"Howdy! I'm FLOWEY! FLOWEY the FLOWER!" He introduced in a saccharine tone. "Hmmm… You're new to the underground, aren'tcha? Golly, you must be _so_ confused! Someone ought to… teach… you…"

Flowey stopped his speech when the stranger stepped forward. It wasn't a human at all! It was a white fox monster. She was short, about five feet tall, and small in stature. She was wearing strange clothing: a black shirt with no sleeves, red jeans, black leather fingerless gloves, sand flat black shoes. There were two earring on her right ear, one black and the other red. She had a weird black crescent moon mark on her muzzle. But that wasn't the strangest part. The monster's blood red eyes were boring holes into the flower, as if she was restraining herself to not kill him.

"No way… you're a monster… how did you…?" Flowey stammered, staring up at the fox monster. "Who are you?!" Something was way off. What the hell is going on?!

The monster took another step towards Flowey threateningly.

"Are you braindead? _Answer me!_ " Flowey shouted, his face changing into a scary grin.

Another step was taken. She was standing right in front of Flowey, arms crossed.

"…" Flowey was speechless. There was something really off.

The monster lifted a gloved hand in the air, a red aura emitting from her palm.

That's when Flowey knew he was in trouble. She wasn't just any normal monster. She was a little _killing machine_ , not so different from himself _._ He could see it in her eyes. And he could sense it in her soul.

Flowey quickly disappeared in the ground, frightened for the first time in his soulless life.

The monster lowered her hand, sighing. She pressed a tiny button on the black earring.

"Audio diary day one." She spoke. "I'm about to enter the Ruins in the underground. No signs of the child here. There was, however, a little flower that thought it could trick me. He showed his true colors soon enough. They were right. No monster, no matter how big or small, can be trusted."

Polari glanced a golden glimmer. She stopped to stare at, but didn't interest her enough to go near it.

After pushing the button again to end the recording, Polari entered the ruins, ready to destroy any monster that got in her way.

* * *

Toriel sighed in defeat as Frisk left the Ruins. She bit her lip as she trudged back to her house.

 _Why does this pain feel so familiar to me?_ She wondered sadly. _There have been six other children, but for some reason, this feels different…_

Toriel's phone buzzed. She had received a text notification that the puzzles have been activated again.

"That's odd." Toriel murmured. "Is it… another child? I must go investigate."

 _ **~.~.~**_

"You've got to be kidding me." Polari seethed after she fell through a hole for the seventh time. "What kind of place is this? Only dumb monsters would put up a sign that says 'don't step on the leaves,' have me walk on them anyway, and have a sign chastise me for it."

Polari was not expecting to be facing off with puzzles. She was expecting diabolical monsters to be coming after her. Instead, she was trying to figure out a maze. How anticlimactic.

So far, Polari had come across signs that were obviously meant for a child, arrows pointing to the obvious switch for a puzzle, a dummy, little frog monsters that weren't even worth killing, a bridge of spikes (she decided that wading through the water around the spikes was much simpler), and now this.

She walked back up to the puzzle, remembering which way was not the right way, and made it across. She then spotted another Froggit. Not in the mood for more messing around, Polari snatched up the Froggit.

"Tell me how to leaves these ruins." She snapped, fresh out of patience.

The Froggit stared at her in defiance, already hearing from other Froggits and Whimsums that this new monster was trouble.

Polari glared at the frog. "Tell me, _now_."

The Froggit's eyes remained unchanged, fearless.

"Ribbit, ribbit. (She... _Toriel_ , will stop you.)"

Suddenly, a jolt of pain went through Polari's mind, as a memory tried to resurface.

 _You won't get away with this! My family will stop you!_

"No… I won't let it…!" Polari clenched her teeth and hands, choking the Froggit. A burst of Polari's monster magic incinerated the Froggit instantly, leaving behind only dust.

Calming down, Polari wiped the dust on her pant leg, not bothered by the death. Other monsters in the area that witnessed the horrific act fled, making a point to warn others along the way.

 _I was hoping the first casualty would be a monster more… formidable, but whatever. All of the monsters down here are evil. Even if they didn't take part directly, they all acknowledged the murder of six children, and did nothing._

Polari walked forward, shoving her hands in her pockets. _I must remember my mission and nothing else. When I mind this missing child, whatever their name is, I will bring them back home to the Surface. I will avenge the deaths of the six children and kill the monster king, Asgore. And when I find the one responsible for causing time to alter, I will kill it. These monsters will not succeed in their plan to take over the Surface!_

 _ **~.~.~**_

Just as Toriel was about to investigate the mysterious puzzle activations, she was shocked to find Moldsmals, Whimsums, and Froggits approaching her house.

"What is the matter?" Toriel blinked.

"Ribbit, ribbit! (There's a fox monster that killed one of us!)"

"Rumor has it that she came from the portal outside Mt Ebott." A Whimsum added meekly.

"A monster from the Surface?" Toriel frowned. "Oh dear. Everyone, go and hide! I will deal with this myself."

Without looking back, Toriel rushed ahead.

 _Could this be a traitor? Or… the traitor that helped seal all of monsterkind underground?!_

Toriel stopped when she spotted a white furred monster walking towards her.

 _That must be her…_

"Please stop right where you are." Toriel commanded firmly.

Polari stopped, smirking. "You must be Toriel. You're just some goat. Oh, this is just precious. Are all the monsters down here frail and weak? From what they were telling me before I came here, they made you all out to be potent."

"They?" Toriel repeated, her frown deepening. "Who sent you here?"

"Sorry, that's classified." The short monster snickered. "Now, if you tell me where the human is, I may spare your life."

Polari was lying. There was no doubt the human couldn't have gotten through the Ruins without coming across Toriel, thus helping send them to their execution. So, Polari will deliver the same fate.

Toriel gasped. _She's after the child! I must destroy the exit to the Ruins!_

While Polari somewhat had her guard down, Toriel shot a fireball in her face, temporarily blinding her.

"Aaugh!" Polari cried, covering her face with her hands.

Toriel ran back to her home as fast as she could. All she could think about was Frisk's safety. After running down the stairs and through the long hallway, she finally came to the exit. She aimed her fireballs at the door. However, something knocked the wind out of her, almost depleting her HP. Toriel laid on the ground, coughing.

"You know, you're not very good at running." Polari towered over the goat monster. "Hell, those little frog monsters ran faster than you. You see, I may be smaller than you, but I more than make up for it in skill. I honestly could have killed you just now, but I need some information from you."

Toriel gritted her teeth, the wound on her back getting more painful each second.

"I'm not telling you a thing." Toriel said as calmly as she could. "You will not hurt my child."

" _Your_ child?" Polari almost choked. "That's a funny joke."

Polari put her hand against the exit door, feeling the coldness of the outside.

"Maybe I should skin you so I can have a fur coat to continue my mission." Polari mulled.

Toriel only grunted.

"Sorry, I've been told that I have a sick sense of humor." Polari shrugged.

"Please… don't hurt anyone out there." Toriel begged, knowing this was probably the end for her. "Because if you do… Asgore will destroy you."

Polari scoffed. "It's too late for mercy. As _bore_ is no threat to me."

Before Toriel could say anything else, Polari shot an aura orb at Toriel. Without looking back, Polari exited the ruins, only to find a green patch with nothing there.

"Weird." Polari moved on, passing the final door.

Flowey was watching from behind, intrigued with Polari's choices.

"She killed a Froggit out of sheer frustration about something, but killed Toriel out of malice." He grinned sadistically. "Interesting. With the right kind of influence, she could help me destroy this world. I'll be able to kill the human as well. Hee hee hee!"

Flowey disappeared below ground.

* * *

Sans was asleep as his post in Snowdin. After helping Papyrus with his "puzzles," he went back so the human could "fight" Papyrus.

 _what is this kid lookin' for?_ Sans thought in his subconscious. _they have reset so many times now. should i reveal to them that i know about the save files, loading, and resets? maybe then i'll get an understanding._

Sans could sense someone walking past, but was too lazy to open his eyes. It was then that he remembered that usually around this time, he goes over to the exit doors of the Ruins to chat with his lady friend Toriel. He has met her so many times before Frisk reset, but he refused to let Toriel know.

Sans stood up and stretched, his bones cracking. He saw no sign of the person that walked by. Shrugging, he headed to the doors and knocked.

"hey tori! you there? i came up with some new material." He announced proudly.

But nobody came.

"tori…?" Sans was surprised. In every timeline, Toriel was always there at the exact time. What's different now?

Suddenly, he could hear some shuffling and groans.

"tori!" Sans banged on the door. "what's goin' on in there? you okay?"

"You…" Toriel wheezed, hanging on to one HP. "You've got to… protect this human child… please…"

"what…?" Sans was confused. This has never happened.

"There's a fox monster…from the Surface… after the child, named Frisk. She almost killed me… trying to get information… about their whereabouts." Toriel coughed hard.

San couldn't believe his nonexistent ears. There's an anomaly in this timeline?

"tori, i promised you that i'd protect humans that came through here. frisk won't be any different." Sans assured Toriel. "but what about you? you don't sound too good."

"I'll be fine." Toriel replied, not sounding very convincing. "I'm hanging on to my life for as long as I can. If I can make it back to my house, I'll eat to restore my HP. Please… go!"

Upset, Sans did as he was told and ran, hoping this fox monster doesn't hurt anyone else.

 _why in this timeline is there some random fox monster after frisk? from the surface, no less? i just hope papyrus hasn't confronted this fiend yet!_

* * *

 **If you read my explanation for Polari, you know why she's such a dick. XD like I said, she's loyal to the cause and sarcastic. And since she believes that monsters are in the wrong, she's cruel and extremely sarcastic towards them.**

 **I apologize if this chapter was boring. I suck at intro chapters. But hey, more action will be coming next week, as Sans and Papyrus get in on this adventure.**

 **If you want, please leave a review! Some feedback would be nice, since I haven't written much of anything in a while.**

 **Thanks!**

 **PRK**


	2. Chapter 2

**Hey guys! Thank you so much for the faves and follows! It motivated me to keep writing! So thank you again, and enjoy the chapter~**

* * *

 _ **Chapter 2**_

 _ **~.~.~.**_

Polari wished she had followed through and skinned Toriel for a coat when she had the chance. Even though Polari had a thin layer of white fur, it wasn't enough against the frigid cold. Her clothing, which was strategically chosen, didn't help much either.

She rubbed her gloved hands up and down her arms, hoping to create a little bit of friction. But it was no use.

As she trekked the forest, she came across a gate.

"This is the most pathetic gate I've ever seen." Polari scowled in disbelief. "The bars are too far apart!"

Polari stepped right through, irritated. _What's the deal with these monsters? How can such inefficient security be allowed? This is almost too easy. I'm having trouble figuring out how these clowns captured six children!_

There was a sentry station not too far ahead. There was a short skeleton wearing a blue hoodie sound asleep, snoring quite loudly. Polari was tempted to slap the taste out of his mouth, if he had taste buds, for sleeping on his job.

 _Even their sentry is useless!_

Not even wanting to waste her time with the skeleton, she continued on. Her stomach growled.

 _Damn it… is there any way to get food around here?_

After what feels like ages, Polari spotted a tall light blue rabbit monster with a vendor, selling something called nice cream. He looked really happy.

 _Nice outfit, dork._ Polari snickered at his bright yellow shirt and bright red pants. _You look like the mascot of McDonalds'._

Trying to keep a straight face, Polari approached the vendor.

"Excuse me, can you tell where I am?" Polari asked innocently, her hands clasped in front of her

The Nice Cream Vendor's heart melted at the little monster. He smiled brightly. "You must be new, kid. You're in Snowdin Forest."

Polari's small size was also strategic. With a little bit of acting, Polari could go from scary to sweet.

"You know, there was a kid a little shorter than you that came through here not too long ago. They were new, too." The Nice Cream Vendor sighed.

"Is there a place… _warm_ , I could go?" Polari inquired, not in the mood to listen to his stories.

"Why, yes! In town, there's Snowdin Inn, a library, and if you're hungry, there's a shop and a popular restaurant called Grillby's!"

She didn't need a place to sleep or read dumb monster books. She needed a place to warm up and possibly get some food.

"How do I get to Grillby's?" Polari demanded.

After pointing her in the right direction, the Nice Cream Vendor asked, "Do you want some Nice Cream for the road?"

Polari stopped walking and turned around. She lifted a hand, and a red aura shot out and hit his vendor, bursting into flames.

He shrieked, his ears drooping and his expression was one of horror. The nice cream melted from the heat onto the snow. Slicks of red, blue, yellow, and green painted the snow, as if a clown exploded. He backed away in fear, stumbling and falling on the ground.

Polari knelt by the burning vendor and took 15G.

"Wow, your business isn't doing so well, huh?" She asked mockingly, standing back up. "One nice cream is 15 gold. Well, I'm doing you a favor. Or, should I say, a _flavor._ You'd be in poverty before you knew it."

She stashed the gold in her pocket and smirked at the Nice Cream Guy. "And this money is in exchange of keeping your life."

She walked away, satisfied of relieving her frustration on the monster.

 _Wait, that monster mentioned a new kid. I wonder if he was referring to… the human child._ She wondered. _If so, they must still be in Snowdin._

Grillby's was as good a place to start. Using her tactics, she was sure to gain some valuable information.

As Polari trudged through the snow, she passed through what looked like easy puzzles that were already completed.

 _Why is this damn place filled with puzzles?!_

There was another golden glow, just like from the Ruins.

 _Huh._

After walking for fifteen more minutes, Polari was surprised at what she saw when she entered town. A sign greeted her with _Welcome to Snowdin_. There were homes, snowmen, and Christmas decorations up. It almost looked like the Surface. Not that she had been able to explore it that much.

There was a tall Christmas tree with presents underneath. Adult monsters were outside talking while the monster children played. Another memory tried to resurface, but not wanting to cause a scene before getting any information, Polari quickly silenced it.

After passing a shop, the inn, and the library, she finally came across Grillby's. The heat that enveloped her upon her entrance made her sigh in relief. Scanning the restaurant, she took in the patrons and the atmosphere.

At one table there were four weird looking dog monsters. Two looked like reapers with their hooded cloak and axes, one was shifty eyed, and the other was huge with armor. Weirded out, she passed by other monsters and sat at the bar table. A fire monster wearing glasses, a nice shirt and pants, who she assumed was Grillby, silently handed her a menu.

Polari winced at the prices of the food. The 15G she stole wasn't much money at all. She barely had enough for one of the small meals. She glanced to her left, noticing that a red bird monster was eyeing her. A lightbulb lit up in Polari's head. Despite being cold, Polari was thankful for the clothes _they_ made her strategically wear.

Polari removed the tie that kept her black hair in a ponytail, fanning it out with her hands. She then crossed her legs and crossed her arms, making sure it pushed her breasts together. Red Bird stiffened, not taking his eyes off of her.

She turned her head and smiled at Red Bird. He blushed and cleared his throat.

"I-I've never seen you around here before. You from out of town?" He asked.

Polari nodded. "Yes, I am. I've been travelling a lot. I've never been to Snowdin before. I haven't eaten in a while, and I don't have much money…" She sighed with mock sadness.

Red Bird sat up straight in his seat. "I'll pay for it, miss! Order whatever you like. I can't stand to see anyone in need suffer."

 _More like you can't stand to see anyone with boobs suffer._ Polari spat venomously in her head, but she smiled anyway. "Really? Thank you so much!"

Polari ordered a burger, and Grillby went to the back to put the order in.

"So, where are you from? Why are you here?" Red Bird asked, scooting his stool closer to Polari's.

She was disgusted by his shameless advance. "I'm from the town next over, but I don't wanna talk about it." Polari lied, creating tears.

"Oh, Waterfall? T-That's okay!" Red Bird assured her. "You don't have to talk about it! You must have been through a lot, huh?"

 _Waterfall. So that's my next location._

Grillby returned with Polari's burger. She tore into it ravenously, her fangs ripping the meat apart like a wild animal. Red Bird sighed dreamily as Polari ate. The burger was gone in mere minutes. Satisfied, Polari pushed her plate away.

"Do you know anything about a _human_ passing through here?" Polari asked casually.

Entranced by Polari, the bird monster nodded. "Uh-huh. They were in here not too long ago. I think they're about to leave Snowdin, which is shame. They put smiles on members of the Royal Guard's faces." He pointed to the table of dogs.

 _Royal Guard? So they do have some sort of security. And the human managed to make it past them? Extraordinary._ Polari thought.

"I see." Polari stood up, retying the tie back on her hair. "Thanks."

"Will I see you around?" Red Bird asked eagerly.

"…maybe." That was all Polari said before strutting out of Grillby's, her new objective to find a way out of Snowdin. She couldn't ask the dumb bird how to leave, since she got him to believe she's actually from the Underground. She knew how to not let her lies catch up to her.

 _I hate pretending to be a helpless dame._ Polari fumed. _That monster's tongue was practically hanging out of his mouth. Well, this town isn't that big. I'll find a way out myself. I don't need anyone's help. I don't want too much attention drawn to me now._

* * *

Sans was running as fast as he could. He had to find Papyrus! He was sure that the "fight" between him and Frisk was finished. If this fox monster could harm innocent Toriel, who knows who else she could hurt?

Sans heard sobbing, and he hurried towards the noise. It was the Nice Cream Vendor, sitting in the snow.

"hey, hey! what happened here?" Sans asked frantically.

"There… there was a girl." Nice Cream Vendor hiccupped. "A fox monster. She seemed so nice… but then she did _this_. Destroyed my vendor. And she robbed me. Then, she told me a pun that was just as bad as your usual ones."

Sans scowled at the jab. "do you have any idea where she could've gone?"

"Grillby's." He replied. "I told her how to get there."

 _damn it._

"you better get outta here and back home." Sans suggested. "because someone's about to get dunked on. i'll help you replace your vendor soon."

Sniffling, Nice Cream Vendor did as he was told, leaving the wreckage behind.

Sans continued running into town. Papyrus was walking out of their house towards Grillby's, humming a tune.

"papyrus!" Sans shouted, stopping right in front of him.

Papyrus gasped. "WOWIE, SANS! I'VE NEVER SEEN YOU RUN SO FAST IN YOUR LIFE! I, THE GREAT PAPYRUS, AM PROUD OF YOUR EFFORTS! IS YOUR NEW YEAR'S RESOLUTION TO LOSE WEIGHT? BECAUSE I RECOMMEND WEIGHT WATCHER'S-"

"papyrus, we have other things to worry about!" Sans interrupted him, letting the jab at his stature slide for now. "where's the kiddo?"

"THE TINY HUMAN? WE JUST FINISHED OUR HOT, PIPING DATE!" Papyrus announced proudly. "THEIR FIERY PASSIONS FOR ME WERE INCREDIBLE! UNFORTUNATELY, I DID NOT RETURN THEIR FEELINGS. THEY WERE ALSO LOOKING FOR YOU, BROTHER, BUT THEY LEFT A FEW MINUTES AGO TO WATERFALL."

Sans sighed in relief. "good. now, there's been a bit of a situation. we need to be on the lookout for a fox monster. she has hurt quite a few monsters, and is after frisk. she might be in grillby's right now. i'm goin' in. you go by the entrance to waterfall and see if the kid made it there."

"UNDERSTOOD, BROTHER! I, THE GREAT PAPYRUS, WILL PROTECT THE HUMAN FROM ENDANGERMENT!" Papyrus vowed.

The two split up. Sans walked into Grillby's trying to act as casual as possible, as not to scare off the fox monster if she was inside. Nothing matching Toriel's description was in Grillby's. He noticed Red Bird talking to Grillby about something intensely. Sans sat on the stool to the right of him.

"sup."

"Sans! You're late." Red Bird told him. "We were beginning to wonder what happened to you."

"somethin' came up." Sans shrugged. "and i can't stay here long. i have a _bone_ to pick with someone."

"That's too bad! You missed what happened." Red Bird sighed dreamily.

"missed what?" Sans asked, suspicious.

"There was this beautiful fox girl that came in. I never did catch her name. She was cold and hungry, so I offered to buy her some lunch. She was so sweet.

Sans felt uneasy. The way Red Bird was describing her was the _polar_ opposite of Toriel's description. But like Flowey, looks can be deceiving. This girl hurt people. There's no way she's that innocnet. Probably used him to buy food.

"was there anything… _strange_ about her?" Sans inquired.

Red Bird tapped his chin. "No, not really. Her eyes were fascinating, though. Usually red eyes like hers are scary, but on her, they were cute. And the way she ate… it was fascinating too. She ate like a feral wolf after its kill-"

"how long ago did she leave?" Sans asked, not wanting to listen to his romantic blabbering.

Red Bird smirked. "Ah, you wanna get a look at her too? Heh, I'd ship it. Just be careful, though. She's a litter taller than you, but she's so tiny. Don't break her in half."

That _really_ made Sans feel uneasy. He assumed the fox was a big monster. And if she's after Frisk, she could trick them into trusting her. Wait… speaking of easily gained trust…

Sans gasped.

 _papyrus! he's at waterfall!_ He stood up quickly. _i have to warn him that this monster isn't as innocent as she might look!_

"well, gotta go. I can't keep this fox _bonely_ for too long." He joked.

Sans made a quick exit as Red Bird snorted at the pun. He took out his cellphone and called Papyrus.

 _c'mon, c'mon, pick up!_ Sans willed internally.

No answer.

"shit!" Sans booked it towards Waterfall.

 _ **~.~.~**_

Meanwhile, Papyrus stood at Sans' sentry station in Waterfall, keeping a lookout for the fox monster. He figured Frisk was far away enough by now, so his efforts would be better used for confronting the fox.

 _I SHOULD PROBABLY CALL THE TINY HUMAN TO CHECK THEIR PROGRESS._ Papyrus decided, reaching for his cellphone.

He then realized that he forgot his cellphone at home after his date with Frisk. Usually Sans reminds him, since Papyrus is always busy thinking about and doing lots of things. But Sans wasn't present during the date.

 _SUCH IRRESPONSIBILITY WOULD SURELY MAKE UNDYNE FROWN AT ME! I MUSN'T FORGET SUCH AN IMPORTANT ITEM EVER AGAIN!_ Papyrus thought.

A small shadow made its way down the corridor. Papyrus perked up, excited.

 _IF THIS IS INDEED THE MONSTER, I SHALL DO EVERYTHING IN MY POWER TO BECOME HER FRIEND! ANYONE CAN BE A GOOD PERSON IF THEY TRY!_

 _ **~.~.~**_

Polari was relieved when she finally was in Waterfall. She made several detours, and somehow came across a monster throwing ice blocks in the river. That was… odd. In fact, everything she has seen in the Underground so far has been odd. Nothing like she expected.

There was another sentry station up ahead, like the one in Snowdin Forest. Another skeleton was manning it. He was awake.

 _Are all of the sentries skeletons?_ She wondered. It didn't matter. She had to locate the child as soon as possible before they ended up dead.

This skeleton was tall and skinny, the opposite of the one from earlier. He cocked his skull in confusion for a second when he spotted her, but beamed. He walked out from behind the sentry post and stood proud. She immediately guarded herself.

"GREETINGS, FOX MONSTER! I AM THE GREAT PAPYRUS! I HEARD A BIT ABOUT YOU FROM MY BROTHER, SANS! HE SEEMS TO BELIEVE THAT YOU ARE BAD NEWS! HOWEVER, JUST LOOK AT YOU! IF I DIDN'T KNOW ANY BETTER, I'D BELIEVE YOU WERE JUST A SACK OF BONES! YOU'RE SO TINY AND HUGGABLE!"

Papyrus meant no insult, but Polari was angered.

"Get out of my way, bonehead." She snapped.

"DO NOT FEAR, TINY FOX! I, THE GREAT PAPYRUS, WANT TO BE YOUR FRIEND! IF I WAS ABLE TO BEFRIEND A HUMAN, SURELY WE CAN BE FRIENDS!"

Is this guy for real? Polari blinked, not believing what she was hearing. Well, at least she now knows the child has been through here.

"Tell me where the human is." Polari commanded.

Papyrus's face faltered slightly. "EVEN THOUGH YOU ARE A COOL FRIEND, I UNFORTUNATELY CANNOT RELEASE THAT INFORMATION TO YOU."

"Fine." Another red aura radiated from Polari's hands. "I guess I'll have to pick it out from you. When I'm finished plucking your bones, it'll look like graveyard in here."

 _All monster that stand in my way must die!_

Without any more warning, Polari lunged at Papyrus. Papyrus held out a large hand in defense. Her punch landed directly in the middle of his gloved bony palm, the force of the attack knocking them both backwards. Papyrus righted himself and quickly assessed the damage to his hand. To his surprise, the bone was cracked.

 _THAT'S IMPOSSIBLE… HOW COULD SUCH A SMALL CREATURE POSSESS SO MUCH POWER?_ Papyrus thought worriedly. _THE ONLY OTHER MONSTER TO HAVE EVER CRACKED MY BONE IS UNDYNE, ON ACCIDENT. AND SHE WAS USING FULL FORCE._

The next thing Papyrus knew, Polari was on him again, this time stamping his large foot with her small one.

"OWIE!" Papyrus cried, clutching his foot.

Then, Polari jumped up and kicked Papyrus's chin, sending him flying backwards and hitting a wall. She was about to go in for the kill, when her ears suddenly twitched. Sensing danger, Polari jumped backwards, barely dodging a row of bones jutting up from the ground. If she was a second too late, those bones would have impaled her.

On high alert, Polari spun around. She recognized her attacker.

 _It's that sleeping skeleton from before…_ She realized.

Papyrus groaned as he stood up shakily. "…SANS?"

"get outta here and go back home!" Sans ordered, his glowing blue eye fixed on Polari. "and while you're there, grab your damn phone."

"WHAT ABOUT YOU? I WON'T LEAVE YOU TO FIGHT ALONE!" Papyrus retorted stubbornly.

"do as i say!" Sans told him. "i'll be fine, cuz this girl's about to have a _bad time_."

* * *

 **That's all for now! See you next week for chapter three for a face-off between Sans and Polari! Thank you so much for reading.**

 **I would really appreciate some feedback! Please leave a review if you want!**

 **PRK**


	3. Chapter 3

**Hey guys! Thank you so much for the reviews, faves, and follows! The support really makes my day.!**

 **The plot moves forward! Sans and Polari have their first face-off! Also, shit hits the fan when Polari meets a certain member of the Royal Guard.**

 **Just a side note, I know Napstablook and Mad Dummy don't have a specific gender, but since I'm already using 'they' for Frisk and an unnamed party Polari keeps mentioning, I decided to use 'he' for both to prevent confusion... especially for me.**

 **Enjoy the chapter~**

* * *

 _ **Chapter 3**_

 _ **~.~.~**_

"i'll be fine, cuz this girl's about to have a _bad time_."

Polari involuntarily shivered at Sans' tone.

Knowing Sans was one hundred percent serious, Papyrus did as he was told and left Waterfall.

"Well, well, well." Polari walked towards Sans. "I guess the Underground has some strong monsters after all. I was getting tired of using weaklings as stress relievers. Although, this'll be the first time I'll be fighting someone in pink slippers." She sneered.

Sans narrowed his eyesockets threateningly. "you're gonna regret ever comin' down here."

"Bring it on, you pile of dry bones." Polari stood in her fighting stance.

Sans' shoulder's slumped. "that's racist. that's like me calling you a tanooki suit."

"What? I wasn't making a Mario joke... you know what?! Enough of this chatter!" Polari jumped and stretched her leg out to deliver a swift kick.

Sans easily dodged, causing Polari's attack to make a dent in the ground. She immediately went for an aura powered uppercut.

Sans' blue eye shone brightly as he stretched his hand out.

At that moment, Polari froze. A blue aura surrounded her. She felt a tight hold on her chest before being flung away and landing hard on the ground.

Groaning, she got up from the ground, only to find herself frozen again.

Sans slammed Polari against the wall. She coughed out blood, glaring at the short skeleton. Sans had total control of her soul. There was something odd about it, but Sans tucked it away in the back of his mind.

"i wonder… the pain you're feeling right now, did toriel feel the same when you had her barely hanging by a thread of life?" Sans asked gravely. "i don't even know if she's _alive_ right now."

He pulled her in close, still having an iron grip on her soul. "what about the froggit you _burned alive_? do you feel as helpless and weak as the nice cream vendor felt when you destroyed his only way of making a living?"

He slammed Polari face first on the ground. "you're a rare breed of monster, kid. we never hurt our own. you're lucky i showed up before you got a chance to kill my brother. if you did, it would've been _dead where you stood_."

Sans raised Polari up off the ground. "i won't allow you to hurt the kid. you'll die a painful death before you even lay your dirty paws on them."

Polari was about to say something, but then Papyrus came running back.

"SANS! WE HAVE A PROBLEM!" He said frantically.

"what are you doin' back here?" Sans didn't take his eyesockets off of Polari. "i told you to get outta here!"

"I JUST RECEIVED A TEXT FROM ALPHYS! UNDYNE HAS KILLED THE TINY HUMAN!"

Sans had never seen such a horrified and devastated expression than the one Polari just gave.

 _shit… the kid will reload their save file soon. i dunno how far back they saved. depending on that, this fox and i would have never encountered each other._

Sans released Polari. She crumpled on the ground. He needed to get any sort of information from her before things reset.

"who are you? what do you want with the kid?"

Polari glowered at Sans, her expression lethal. If looks could kill...

"Fuck you, that's what. I'm not here to hurt them. I'm here to rescue them."

Weakened and knowing she couldn't kill Sans at this time, Polari stood up and escaped deeper into Waterfall.

Sans knew she wouldn't make it far before the save file was loaded. Then, before he knew it, he was back outside of Grillby's, Papyrus standing in front of him.

"WOWIE, SANS!" Papyrus cried. "I'VE NEVER SEEN YOU RUN SO FAST IN YOUR LIFE!"

Sans ignored Papyrus's repeated dialogue. All he could think about was the fox girl.

 _if she's here to help the human, why is she hurting the monsters here along the way? she's a monster herself. unless…_ Sans' eyesockets widened in horror as realization struck him. _tori said she came from the surface. which means_ _…she's working for the humans._

"you forgot your phone at home. go get it, papyrus." Sans said. "don't wait up for me. i'm goin' to waterfall for a while."

* * *

Polari was standing next to the monster throwing ice blocks into the river. She blinked in confusion.

 _What… just happened?_

Just then, her red earring beeped. She pressed the button.

"LOAD located at: Waterfall" a generic robotic voice said.

Polari was shocked. _The resets, saves, and loading are real? I thought they were possibly pulling my leg for having me kill a time traveler. So, that means the human is still alive! I ca save them! Wait… what happened before I came back here?_

She racked her brain, when suddenly a skeleton with a blue eye surfaced.

 _Ah… Sans._ She shivered, remembering the pain he inflicted unexpectedly.

Knowing exactly where to go, she hurried towards Waterfall, hoping not encounter the weird skeleton brothers.

 _The weird tall one said the kid was killed by Undyne. I have to find out who this monster is, and kill it before it gets the child!_

Sans was watching from afar as Polari ran in Waterfall. He decided to spy for the time being. It would be unwise to try and fight her again, especially since he didn't know a thing about the extent of her abilities. Was she like him? Was she aware of the altered timelines as well? She ran back in Waterfall in quite a hurry. With… determination.

 _ **~.~.~**_

Polari didn't know where to start. Waterfall was so different compared to Snowdin, or even the Ruins. After passing the sentry station, she continued forward and had to wade through water. She passed to a seemingly random patch of tall grass, across a bridge of pink flowers.

 _It's so dim here… I feel like I'm getting lost._

Polari came across another golden glow.

 _Just what are these? They're everywhere._

Shaking her head, Polari advanced. She came across a sea horse monster flexing his muscles. Aaron winked at her suggestively, flexing even harder. Grossed out, Polari lifted her hand to blast him, but something eerie kept her from following through. She felt like she was being… watched. It made her fur stand up on end at the sudden cold sensation. Polari quickly put her hand down and walked away.

"Why does that remind me of that weird skeleton?" She wondered aloud.

From the shadows, Sans frowned as he continued to follow her.

 _does she really remember me? does she remember papyrus too?_

Unbeknownst to him or Polari, it was another third party watching that made Polari shiver. Gold petals glimmered before disappearing back underground.

 _ **~.~.~**_

Polari entered a room with a few blue flowers. The sign on the wall read 'WISHING ROOM.'

The flower started talking to her when she approached it. In fact, each one talked. From what Polari could gather, it was a brother and sister talking about making wishes to the sparkling stones, since they don't have real stars. Polari felt her cold heart tug.

At the end of the room, there was a path leading to an opening in a wall. Polari quickly went through. There were more signs talking about.

"…the Old War…" Polari said quietly.

 _Why did the humans attack? Indeed, it seemed like they had nothing to fear._

 _Humans are incredibly strong. It would take the soul of nearly every monster just to equal the power of a single human soul._

Polari read each sign one by one, amazed and shocked at this information. She wasn't educated enough on the war between monsters and humans. She only learned that the war was the monsters' fault, and they're all evil. Could that be… wrong?

The fourth sign made Polari nervous.

 _If a monster defeats a human, they can take its soul. A monster with a human soul… a horrible beast with unfathomable power._

"I gotta find the human!" Polari continued forward. "If Asgore is the cause of the resets, is it because he couldn't retrieve this child's soul? Wow… _they_ were right. Asgore really does want to destroy humanity. Imagine what'll with seven human souls… he'll become a beast."

Suddenly, Polari's sensitive ears picked up a battle cry in the distance. Her eyes widened. She ran at breakneck speed towards the sound. Sans had said that monsters don't harm their own kind. Which means only one thing… it's hurting the human.

 _ **~.~.~**_

Polari had no idea how fast she was running. Her surroundings were all a blur. She vaguely remembered passing by a telescope, more of those weird flowers, a giant onion shaped water monster, a stone statue with an umbrella, and tricky platforms.

It was then that she spotted a tall monster draped in armor, red hair sticking out from the helmet. And… a human child was standing behind it.

 _The human! So, is that Undyne?!_ Polari wanted to shout at the monster, but before she could, Undyne sent forth her spears, destroying the path Frisk was on, plummeting below. Polari froze, not believing her eyes.

Satisfied, Undyne disappeared. As soon as she did, Polari ran and jumped down, not caring if she died in the process. _They_ warned her not to come back without the human. And if _they_ found out she let them die twice? Unforgivable.

Polari landed on her feet in a bunch of golden flowers, like she did when she first entered Mt. Ebott.

 _The human's body should have landed here. Does that mean… they're alive?_

Polari put all of her hope on that idea as she ventured forward. As soon as she receives some sort of confirmation about the kid's well-being, she would hunt down and kill Undyne.

Polari walked on ahead. She waded through more water, filled with garbage. Up ahead was a dummy. She could hear him muttering to himself about a Napstablook (whatever that is), acid rain, and a human. She walked past it, but deciding it was worth asking, she turned around to address the dummy.

"Where did the human go?" Polari asked firmly.

"The _human_?" Mad Dummy shouted. "That brat! I had them too, but then that damn Napstablook ruined the fight for me! If he wasn't a ghost, I'd give him what for!"

"I thought monsters don't hurt their own kind." Polari scoffed, echoing Sans from earlier.

"Shut up, you furry freak!" Mad Dummy screeched. "I'm so mad, I oughta-"

 _Crunch._

Polari pulled back an aura powered fist and punched Mad Dammy square in the face. The force cracked the dummy's face.

Terrified, Mad Dummy tried to escape, but Polari grabbed his neck, her eyes boring holes into him.

"Tell me where the human went, or else I'll scare _your_ soul out of your body." Polari growled hazardously.

That was not a threat. It was a promise.

"T-They went towards Napstablook's house! Just keep going north, and you'll find it!" Mad Dummy stammered.

"Thanks." Polari then used her magic to blast a hole in him, instantly turning him into dust.

After soaking her gloved hands in the dirty water, she left to go find this Napstablook's house.

 _ **~.~.~**_

Sans' brow furrowed after he watched Polari's encounter with Mad Dummy. There was nothing he could've done in time to save Mad Dummy from his gruesome fate.

 _there's something not right with her soul._ He thought. _when she was in the wishing room, her soul seemed to change drastically. it was docile and compassionate. but when she confronted the mad dummy, it changed again. her soul was full of anger, bitterness, and… hate._ _it's as if her soul has two split personalities. when frisk first came here, they killed undyne and mettaton. and their soul never radically changed like that. it was a slow change. even undyne's soul is tame. what's different about her? there's also the fact that somehow, despite a reset, she remembered me._

Sans sighed. _i have a theory on what might be different, but i'll need more evidence first. as soon as i can catch her when she's not as deadly, i'll make my move._

 _ **~.~.~**_

Polari came across two houses close together: one white and gray, the other orange. She knocked on the orange one first. No answer. She knocked on the gray one. No answer.

"Goddamn it." Polari seethed, pissed that the dummy gave her wrong information.

Just then, the door slowly opened. A ghost wearing headphones peeked out.

"O-Oh… hello. You must be here for Mettaton. No one ever comes here for me. This is the wrong house. Sorry."

Napstablook was about to close the door, but Polari stuck her foot in its path.

"No, I heard there was a human with you?" Polari clarified impatiently.

"O-Oh… wait, I remember you." Napstablook said. "I saw you in the Ruins. I wanted to say hi, but you looked like you were having so much fun with the Froggits. I didn't wanna interrupt you…"

Polari blinked in disbelief. What the hell is happening right now?

"Then I heard the same Froggits say to stay away from you because you were a homicidal _freak_ … oh no…" Tears streamed down Napstablook's incorporeal form. "I failed them. I didn't stay away from you. I'm standing here talking to you. I am a failure… o-oh…"

Polari visibly flinched at the word 'freak.' If someone calls her 'freak' _one more time_...

"I wanna kill him so _bad_ …" Polari muttered under her breath.

"Oh… I'm a ghost, so I can't die. I'm sorry to disappoint you… I would let you murder me if I could… oh…"

"The _human_ , Napstablook. Where's the human?" Polari snapped, irritated.

"O-Oh. The human. They were here. We hung out here and felt like garbage together. Then they lost the Thundersnail race, and that's when they left. They must have been angry… oh…"

"Do you have _any_ idea what direction they went?" Polari asked through clenched.

"I dunno…"

"GODDAMN IT!" Polari shouted, her patience gone.

"Oh… I'm sorry…" Napstablook apologized. "Maybe you can ask Undyne… her house is west of here… But be careful. She's _really_ scary."

Polari left without another word, hurrying west. This child killer has a _house_?

Polari ran up to a scary looking fish shaped house. She kicked the door down. Of course, this Undyne was not at home. Growling in frustration, she was about to destroy the house out of spite. Deciding not to waste any more time, Polari restrained herself.

 _ **~.~.~**_

Polari walked into a maze of blue lights. She was sure she had gotten lost until she walked down into a town of… cats? Dogs? Polari looked at the sign. It read ' _hOI! welcom to…TEM VILLAGE!_

These monsters all looked the same, with had white fur and black hair. Curious, Polari approached one.

"hOI! im temmie! and dis is my friend, temmie!" Temmie greeted her.

"Nope." Polari quickly left Temmie Village, walking through the maze in a different direction.

Just then, her ears picked up another cry. This time, it was a cry for help.

" _Yo, w-w-wait! Help! I tripped!"_

It was coming from up above. As fast as she could, Polari navigated the rest of the confusing maze, hoping she wasn't too late. She waded through water and continued up, passing by more Echo Flowers, whispering about a wish a couple had. Polari started to get anxious. Waterfall is so huge. How on earth did the kid navigate it so quickly?

She saw an orange armless monster child heading her way. He was humming to himself happily. It was the same tone that cry for help was.

"Hey, kid! Have you seen a human around?" Polari asked urgently.

"Yeah, dude!" Monster Kid replied gleefully. "They like, saved my life and stuff! They're so awesome! Just up ahead. I protected them from my idol, Undyne!"

Polari took off, feeling dread spread through her. Another golden glow greeted her. Something inside was telling her to go touch it.

 _What even is this thing? Why is it so… enchanting?_

Polari touched the glow. Then, words flashed through her mind.

 **Polari LV2**

 **Waterfall**

 **File Saved**

Polari was brought back to reality.

"File Saved? What the hell? Are these the... save files?"

Polari backed away from the save point and ran away.

 _No, no, no! Why? There's an evil monster doing these save files! Not me!_

"You know what… SCREW IT!" A voice cried.

Polari stopped in her tracks at the sound of yelling. She saw Undyne, yelling at the human child. Her helmet was removed, revealing a fish monster with long red hair in a ponytail. She donned an eyepatch on her left eye.

 _This is my chance!_

As Undyne continued to shout at Frisk, Polari quietly climbed a mountain nearby. Frisk saw this, looking at Polari in confusion.

"What the hell are you looking at, punk?!" Undyne screeched at Frisk. "You're about to die! SO PAY ATTENTIO-"

Polari jumped and kicked Undyne's head, sending her down the mountain and onto the ground. Frisk blinked in confusion. No other timeline went like this before. In fact, Sans and Papyrus haven't appeared in their usual places.

"WHO DID THAT?!" Undyne demanded, standing back up.

Polari crossed her arms as she stood on the mountain, glaring at Undyne. "You will leave the human be! If you don't, I'll kill you."

Undyne gawked. "And who the hell do you think you are?! Are you a dumbass? That human has the final soul needed to make King Asgore a god and break the barrier! Then, all of us monsters will be free!"

"And that's exactly what I'm here to stop." Polari growled. "The human leaves with me. And your king… will _die_ by my hands!"

"Traitor!" Undyne screamed, materializing a spear. "You're no monster! You might as well be a human! Thus, I'll treat you as such!" She lunged at Polari. The fox dodged the attack and used her magic to form an orb of red energy. Undyne blocked the attack, and shot several spears at her.

 _Finally! An opponent worth fighting!_ Polari thought, adrenaline surging through her.

Frisk watched the fight in total confusion. Suddenly, someone grabbed her arm from behind.

"shhhh. kid, it's me." Sans whispered to the startled Frisk. "there's… somethin' i have to tell you. come with me."

Polari found an opening and shot aura bullets at her. Undyne gritted her teeth in pain.

"That's _it_!" Undyne released dozens of arrows in Polari's direction.

Unable to recover quickly enough, several of them gored her, depleting her HP.

"…chhhg!" Polari choked on her blood as she crumpled to the ground. The light left her eyes as blood pooled around her.

Then, everything went black.

* * *

 **Oops! A shameless cliffhanger. Although, I'm pretty sure you guys know what'll happen next ;)**

 **I should rename this story to 'Polari Gets Thwarted by Every Monster in the Underground.' It has a nice ring to it. You're probably wondering why Polari, a monster, could use a save point, let alone see them. Ah, that is quite the question. I wonder who can figure it out first?**

 **Also, is it just me, or is Waterfall just an endless maze of confusion? If I ended up down there, I'd never find my way out.**

 **Thanks for reading! Reviews and feedback are always welcomed and appreciated!**

 **The plot thickens in the next chapter. See ya soon!**

 **PRK**


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